The therapeutic success of the most diverse dialysis methods is based, inter alia, on the use of different buffer substances with the aid of which a modified acid-base metabolism of patients suffering from renal insufficiency can be corrected. Against the background that the acid-base metabolism cannot be corrected by diffusion during dialysis, frequently a supply of buffer substances is required. For balancing the gradient between acids and bases especially bicarbonate and, respectively, a bicarbonate buffer solution is suited. The bicarbonate buffer solution is produced for hemodialysis preferably immediately before or during the treatment. Accordingly, a receptacle, especially a cartridge-shaped receptacle/a cartridge containing a bicarbonate concentrate powder is connected to a fluid source, for example a water source, the water flowing through the receptacle dissolving the bicarbonate concentrate powder present in the receptacle and flushing the latter into the dialysis solution.
The known cartridge-shaped receptacles/cartridges basically include a fluid inlet connecting port/connector and a fluid outlet connecting port/connector to each of which a fluid inlet line and a fluid outlet line can be attached. The connecting ports/connectors basically consist of short pipe sections or pipe nozzles axially protruding from the receptacle. In order to be able to ensure or guarantee a durability of bicarbonate cartridges which is worldwide uniform, i.e. independent of temperature, pressure and air humidity, it is known from prior art to attach or screw end caps having a sealing function onto the pipe nozzle-type connecting ports/connectors.